Use of Predictive Weather Uncertainties in an Irrigation Scheduling Tool Part I: A Review of Metrics and Adjoint Methods

Irrigation management consists of many components. In this work we review and recommend rainfall forecast performance metrics and adjoint methodologies for the use of predictive weather data within the Colorado State University Water Irrigation Scheduler for Efficient Application (WISE). WISE estimates crop water uses to optimize irrigation scheduling. WISE and its components, input requirements, and related software design issues are discussed. The use of predictive weather allows WISE to consider economic opportunity‐costs of decisions to defer water application if rainfall is forecast. These capabilities require an assessment of the system uncertainties and use of weather prediction performance probabilities. Rainfall forecasts and verification performance metrics are reviewed. In addition, model data assimilation methods and adjoint sensitivity concepts are introduced. These assimilation methods make use of observational uncertainties and can link performance metrics to space and time considerations. We conclude with implementation guidance, summaries of available data sources, and recommend a novel adjoint method to address the complex physical linkages and model sensitivities between space and time within the irrigation scheduling physics as a function of soil depth. Such tool improvements can then be used to improve water management decision performance to better conserve and utilize limited water resources for productive use. Editor’s note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

Long-term changes in fish mercury levels in the historically impacted English-Wabigoon River system (Canada)

The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lake Whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. For all lakes and species, there is a significant decline (36-94%) in mercury concentrations through time; however, there is evidence that this decline is either slowing down or levelling off. Concentrations in the English-Wabigoon fish are elevated, and may still present a potential health risk to humans consuming fish from this system. Various biotic and abiotic factors are examined as possible explanations to slowing rates of decline in mercury concentrations observed in the mid-1980s.     

Competitive interactions between co-occurring herbivorous gastropods

The competitive interactions between two species of limpet, Patelloida alticostata (Angas), and Cellana tramoserica (Sowerby) were investigated at two sites; a low-lying intertidal platform and an adjacent subtidal reef located in southeastern Australia, during 1977 and 1982. C. tramoserica was relatively more abundant and larger in shell length than P. alticostata at the intertidal site, but P. alticostata was the more abundant species subtidaily. Fences were used to enclose various combinations of the two species to compare both intra- and inter-specific interactions. By repeating this design at two different, but adjacent sites, it was possible to test the generality of any interactions, and to investigate whether the nature of these could explain the observed differences in the relative abundances between the two sites. Intraspecific increases in density affected C. tramoserica more than P. alticostata at both sites. These effects were manifested both lethally (increased mortality at the intertidal site) and sublethally (as decreased growth and tissue weight at the subtidal site). Interspecific comparisons were asymmetrical, but were similar at both sites: C. tramoserica affected P. alticostata more than P. alticostata affected C. tramoserica. These latter effects were, however, only similar, or minor in comparison with the strong intraspecific effect that C. tramoserica had on itself. This suggests that, as has been found in some previous studies, competitive exclusion of the subordinate species (P. alticostata) is unlikely because of the greater intraspecific effects on the superior competitor (C. tramoserica). Furthermore, because there was little difference in the relative competitive abilities of the two species in the two habitats, competition between the species was probably not responsible for the different relative abundances between the two adjacent areas.     

A 40+ year record of Cd,Hg, Pb,and U deposition in sediments of Patroon Reservoir,Albany County,NY, USA

Sediments of the Patroon Creek watershed (33 km(2)) are known to contain significant concentrations of heavy metals derived from two industrial sites within the watershed. Mercury Refining, Inc (Mereco) has stored and recycled Hg from 1955 to the present day, and National Lead Industries (NLI) manufactured aircraft components containing Cd, Pb, and U from 1958 to 1984. Here we present the first record of heavy metal deposition as preserved in a 3-m long sediment core collected in 1999 from Patroon Reservoir, a small water body (1.3 ha) downstream of the industrial sites. Bulk sediment samples were collected from the core at 0.05-m intervals and analyzed for total Cd, Pb, and U by ICP-MS and total Hg by CVAAS. Total Hg increases from less than 1 mg kg(-1) (dw) below 1.68 m, to a maximum of 6.2 mg kg(-1) at 0.80 m, and then declines to the sediment-water interface. Total Cd, Pb, and U concentrations increase abruptly above 1.68 m to maximum values of 25, 320, and 3600 mg kg(-1) (dw), respectively, and then decline gradually upwards. By correlating metal profiles with industrial history, we conclude that the 1.68 m horizon was deposited no earlier than 1958, the beginning of aircraft component manufacturing at NLI. The average, apparent sedimentation rate within the reservoir has a minimum value of approximately 0.04 m year(-1) for the 41-year period from 1958 to 1999. In the interval 0--1.68 m, average concentrations of Cd, Hg, Pb, and U are 1.69, 1.50, 461, and 13 mg kg(-1), respectively. These levels are comparable with other lake, reservoir and stream sediments that have been moderately to severely impacted by industrial pollution and are above levels expected to be detrimental to aquatic organisms.     

Prenatal Diagnosis of congenital disorder of glycosylation type Ia (CDG-Ia) by cordocentesis and transferrin isoelectric focussing of serum of a 27-week fetus with non-immune hydrops

Blood was obtained by cordocentesis from a fetus with non-immune hydrops demonstrated by ultrasound scanning at 27 weeks' gestation. Abnormalities of serum transferrin isoelectric focussing (IEF) were identified, characteristic of a congenital disorder of glycosylation type I (CDG-Ia). A diagnosis of CDG-Ia was confirmed by enzyme analysis of cultured amniocytes. This is the first report of CDG-Ia diagnosed by serum analysis in a fetus. Previous reports have warned that diagnostic abnormalities do not appear in serum until several weeks after birth. The sensitivity of cordocentesis transferrin IEF is unknown but is less than 100% effective because cases have been diagnosed postnatally after normal prenatal or neonatal studies. Enzyme analysis or mutation analysis is required for diagnosis of congenital disorder of glycosylation (CDGs) regardless of whether a diagnostic transferrin pattern is identified prenatally. The analysis of a small sample of serum, from cordocentesis, performed to check for fetal anemia, simplified the investigation, diagnosis, and genetic counselling of a case of non-immune hydrops detected at 27 weeks' gestation. This might be a useful test for other cases in these circumstances, as fetal blood is usually collected to check for anemia. Copyright © 2006 John Wiley & Sons, Ltd.     

Social information and community dynamics: nontarget effects from simulating social cues for management

Artificially creating social stimuli may be an effective tool for facilitating settlement by rare and/or declining species into suitable habitat. However, the potential consequences for other community members have not been explored and should be considered when evaluating the overall utility of using such management strategies. I report on nontarget, community-wide effects that occurred when manipulating social cues of two competitors that are species of concern in the western United States, the dominant Least Flycatcher (Empidonax minimus) and the subordinate American Redstart (Setophaga ruticilla). The experiment consisted of surveying birds during a pretreatment year, which allows for the control of baseline communities, and a treatment year, in which treatments were applied just prior to settlement by migratory birds. Treatments included broadcasting songs of flycatchers and redstarts and were compared to controls. While the addition of redstart cues did not significantly influence community structure, the addition of flycatcher cues reduced species richness of migratory birds by approximately 30%. This pattern was driven by an absence of local colonizations of small-bodied migrants to sites with added flycatcher cues, rather than by local extinctions occurring from manipulations. The artificial flycatcher stimuli were more responsible for declines in species richness than were changes in actual flycatcher densities. I conclude by identifying some fundamental issues that managers and conservation practitioners should weigh when considering simulating social cues for species conservation prior to implementation.     

The life history of Rhodophysema georgii in laboratory culture

Rhodophysema georgii Batt., a rare epiphyte on Zostera spp., was collected from lowtide-level lagoons at Bembridge (Isle of Wight), and its life history examined in laboratory culture. The tetraspores, the only method of reproduction known, gave rise to small crusts which again developed tetrasporangial sori on the surface, similar to those of the parental material. It is suggested that this direct type of life history is probably due to the repression of meiosis in the tetrasporangial mother cell.